1. Technical Field
The invention relates generally to a method of predicting an individual's predisposition to QT prolongation, and more particularly, to a method of predicting such predisposition based on a sequence of the individual's ceramide kinase-like (CERKL) gene.
2. Background
Prolongation of the electrocardiographic QT interval (the time between the start of the Q wave and the end of the T wave) is referred to as long QT syndrome (LQTS). LQTS may comprise a genetic component. In some patients with LQTS, QT prolongation can be a chronic condition. In some persons, LQTS may be induced by the administration of an active pharmaceutical ingredient that prolongs the QT interval.
A number of compounds are believed to be capable of prolonging the QT interval. These include amiodarone, arsenic trioxide, bepridil, chloroquine, chlorpromazine, cisapride, clarithromycin, disopyramide, dofetilide, domperidone, droperidol, erythromycin, halofantrine, haloperidol, ibutilide, iloperidone, levomethadyl, mesoridazine, methadone, pentamidine, pimozide, procainamide, quinidine, sotalol, sparfloxacin, and thioridazine.
Other compounds are suspected of being capable of prolonging the QT interval, although such prolongation has not been definitively established. These include alfuzosin, amantadine, azithromycin, chloral hydrate, clozapine, dolasetron, felbamate, flecamide, foscarnet, fosphenyloin, gatifloxacin, gemifloxacin, granisetron, indapamide, isradipine, levofloxacin, lithium, moexipril, moxifloxacin, nicardipine, octreotide, ofloxacin, ondansetron, quetiapine, ranolazine, risperidone, roxithromycin, tacrolimus, tamoxifen, telithromycin, tizanidine, vardenafil, venlafaxine, voriconazole, and ziprasidone.
Individuals at risk of suffering LQTS are advised not to use still other compounds, due to the possibility that they may prolong the QT interval. These include albuterol, amitriptyline, amoxapine, amphetamine, dextroamphetamine, atomoxetine, chloroquine, ciprofloxacin, citalopram, clomipramine, cocaine, desipramine, dexmethylphenidate, dobutamine, dopamine, doxepin, ephedrine, epinephrine, fenfluramine, fluconazole, fluoxetine, galantamine, imipramine, isoproterenol, itraconazole, ketoconazole, levalbuterol, metaproterenol, methylphenidate, mexiletine, midodrine, norepinephrine, nortriptyline, paroxetine, phentermine, phenylephrine, phenylpropanolamine, protriptyline, pseudoephedrine, ritodrine, salmeterol, sertraline, sibutramine, solifenacin, terbutaline, tolterodine, trimethoprim-sulfa, and trimipramine.
The CERKL gene has been mapped by Tuson et al. to 2q31.2-q32.3, between the ITGA4 gene and the NEUROD1 gene, and determined to contain 13 exons. Tuson et al., Mutations of CERKL, a novel human ceramide kinase gene, causes autosomal recessive retinitis pigmentosa (RP26), Am. J. Hum. Genet. 74: 128-138, 2004. PubMed ID: 14681825. Ceramide kinases convert the sphingolipid metabolite ceramide into ceramide-1-phosphate, both of which mediate cellular apoptosis.